In his career, Jesse was a respected archivist, editor and historian, as well as an authority on early Mormon handwriting.[7]Davis Bitton called him one of the "[Mormon] historians who are deeply familiar with the sources on Mormon origins [yet] still find it possible to remain in the fold."[8] In addition to his mission, Jessee has served in his local Salt Lake City congregation as a home teacher[9] and counselor of the high priest group,[10] as well as a stakefamily history coordinator.[11]

While Leonard J. Arrington was researching a book on the Mormon development of western America, he met Jessee in the church archives during 1967. As a cataloguer of manuscripts, Jessee informed Arrington of many useful documents in the archive that historians had not yet studied.[15] Arrington later recalled that at the time Jessee was "Intelligent, well-informed, hardworking, and modest," and that "he knew more about the documents of LDS history than any other person."[16]

In 1972, Leonard J. Arrington became the official Church Historian. He requested the transfer of Jessee from the archives to the new History Division, a newly created, impressive team of historians for researching and writing of new Mormon histories.[4] One such work, Jessee's 1974 Letters of Brigham Young to his Sons, caused ApostleBoyd K. Packer to bring concerns to the First Presidency about the Historical Department's "orientation toward scholarly work," an early sign of the tension that would eventually lead to the History Division's disbandment.[18] Jessee was also assigned by Arrington to locate, collect and transcribe all of Joseph Smith, Jr.'s writings, a work inspired by the Thomas Jefferson Papers of the 1950s and those of other Founding Fathers.[17]

In the 1980s, Jessee was a major player in the Historical Department's examinations of important historical documents produced by Mark Hofmann, which were later found to be forgeries.[19] Jessee was considered the preeminent expert on early Mormon handwriting, especially Joseph Smith's, and he authenticated and defended a number of Hofmann's forgeries,[20][21][22] including the famous "Salamander Letter".[23] Hofmann's extensive deception of document and forgery experts led him to be called "unquestionably the most skilled forger this country has ever seen".[24]

As a Senior Historical Associate[27] then Senior Research Fellow,[28] Jessee served for nineteen years in the Joseph Fielding Smith Institute.[25] During this time he continued his earlier work to produce the papers of Joseph Smith. In 1984, he published most of Smith's own writings and many of his dictations in The Personal Writings of Joseph Smith. This research continued to expand into two volumes of The Papers of Joseph Smith, one in 1989 on Smith's autobiographical and historical writings, and the other in 1992 on Smith's journals.[17]

Jessee's efforts were eventually made an official joint effort of BYU and the LDS Church in 2001, called the Joseph Smith Papers Project. This is intended to be a large multi-volume series, including virtually everything written by Joseph Smith, by his office, or under his direction.[17] That year, Larry H. Miller, a Salt Lake City businessman and philanthropist, began funding the venture. In 2005, Miller announced the goal of completing the project by 2015, "while Dean Jessee is still around", since Jessee was then in his 70s.[29] Jessee is general manager of the project along with Richard Bushman and Ron Esplin.[25]

^Texts from Hofmann's forgeries that Jessee identified as Joseph Smith holographs made it into the 1984 first edition of Jessee's The Personal Writings of Joseph Smith. A corrected second edition was published in 2002.